Tuning the MoS2 Edge-Site Activity for Hydrogen Evolution via Support Interactions

The hydrogen evolution reaction (HER) onsupported MoS2 catalysts is investigated using periodic densityfunctional theory, employing the new BEEF-vdW functionalthat explicitly takes long-range van der Waals (vdW) forcesinto account. We find that the support interactions involvingvdW forces leads to significant changes in the hydrogenbinding energy, resulting in several orders of magnitudedifference in HER activity. It is generally seen for the Mo-edgethat strong adhesion of the catalyst onto the support leads toweakening in the hydrogen binding. This presents a way to optimally tune the hydrogen binding on MoS2 and explains the lower than expected exchange current densities of supported MoS2 in electrochemical H2 evolution studies.